This invention relates to the field of temperature control systems, and more particularly to a method and system for controlling the temperature of an individual room to conserve energy without the sacrifice of occupant comfort.
It is possible to conserve substantial amounts of energy in the heating and cooling of individual rooms if the temperature in each room is allowed to go down or up in the case of heating or cooling, respectively, when the room is unoccupied. This is particularly applicable to motel and hotel rooms where such rooms may be unoccupied for relatively long periods of time. Since the periods of occupancy cannot be predetermined, it is not feasible to use automatic devices such as time-controlled thermostats to reduce room heating and air conditioning in such transient situations.
There are many possibilities for occupant-control of room temperature in a motel or hotel. The manual operation of a thermostat device by which the room occupant would be expected to adjust the temperature setting as a separate operation upon entering or leaving the room is the simplest and least expensive approach to the problem. Unfortunately, it is difficult, if not impossible, to secure the human cooperation required to make this simple approach workable. If an occupant is expected to adjust temperature-sensing equipment each time a room is entered or left, it is unlikely that such adjustment will be made as a matter of course, unless the temperature adjustment mechanism is coupled with an action done automatically upon entering or leaving the room.
There are other available alternatives which could utilize occupant actions such as insertion of the room key into the door lock, opening the door, turning on the room lights, etc., to control the room temperature conditioning equipment to conserve energy. A special box containing a key-activated mechanism could be provided to initiate the temperature change cycle when the occupant inserts the room key. All of the alternatives involving the use of equipment with automatic operation are complex, expensive, subject to failure, and frequently are inconvenient to the room occupant who does not want to enter an uncomfortable room and be bothered with special procedures in order to be assured of a comfortable environment. To justify the installation and maintenance of expensive equipment with automatic operation would require that a considerable temperature difference be programmed between conditions when the occupant is present and absent in order to make the energy savings sufficiently great.